The present invention relates to a contrast agent film rolling device used in a printer.
A thermal transfer system using ink film for printing has been widely used in a printer. The thermal transfer system comprises a thermal head as a printing means, a supply-side-film core supplying an rolled ink film in accordance with the supply of paper, and a film core rolling up the ink film after printing. The cores are disposed ahead and behind the thermal head.
FIG. 7(a) is a perspective view of the printer having the ink film, FIG. 7(b) is an perspective view of an exploded ink film cassette. As shown in FIG. 7(a), the printer includes case 1 and removable ink film cassette 2. As shown in FIG. 7(b), ink film cassette 3 includes cassette housing 3, supply-side film core 4 and roll-up-side film core 5 which are rotatable and removable in cassette housing 3, and ink film 6 rolled up and held with a tension by supply-side film core 4 and roll-up side film core 5.
More specifically, supply-side film core 4 and roll-up-side film core 5 are typically paper tubes made of corrugated paper. One end of virgin ink film 6 is attached to supply-side film core 4, and the other end is attached to roll-up-side film core 5. The paper tube of supply-side film core 4 is usually the same size as that of roll-up-side film core 5. Gear flange 7, which is used for roll-up-driving the cores in the device, is inserted into both ends of each core, and gap 8 is formed in both ends of each core to carry rotation.
When ink film 6 has been used up, a new ink film 6 may be inserted along with new supply-side film core 4 and roll-up-side film core 5. Then, gear flanges 7 are inserted with proper orientation into the paper tubes of film cores 4 and 5. Ink film 6 (along with cores 4 and 5) is placed in cassette housing 3.
It is possible for cassette housing 3 to be replaced in case 1 as a single step. The roll-up side and the supply side film cores must be set in a predetermined position and orientation, and the ink-coated side of ink film 6 must face correctly. Consequently, the user need only place cassette housing 3 in the correct orientation in case 1. A conventional device may comprise contacting piece 9. Contacting piece 9 helps the user to notice whether cassette housing 3 is properly positioned and oriented within case 1.
On the other hand, in another conventional device, for cost reduction, cassette housing 3 is omitted, and only cores 4 and 5 are placed in the device. This device has no feature to prevent cores 4 and 5 from being placed incorrectly. A similar structure to cassette housing 3 can be formed in four gear flanges 7 inserted into cores 4 and 5, and the structure can place cores 4 and 5 only in a predetermined position and orientation in the device. However, there is still a problem that the paper tubes must be placed in the device after checking each core""s position.
Furthermore, regardless of the presence or absence of cassette housing 3 holding film cores 4 and 5, whenever the user places the ink film in case 1, the conventional thermal transfer printer requires the user to make burdensome operations such as observing the orientation of the gear flange placed at paper tubes of cores 4 and 5, and further the orientation of the ink film placed in case 1.
In a printer employing a contrast agent (i.e. ink) film, shaft sections at both ends of a supply-side film core and a roll-up-side film core, have different diameters. Gears are disposed at one end of the supply-side film core and one end of the roll-up-side film core. Supporting sections correspond to the diameters of each shaft section.
In an alternative exemplary embodiment, a holding section is provided for rotatably holding the shaft section of one end of the roll-up-side core, a supporting section for rotatably holding the shaft section in the other end of the roll-up-side film core, and another supporting section for rotatably holding the shaft sections of both ends of the supply-side film core.